<template>
  <div id="root">
    <div class="todo-container">
      <div class="todo-wrap">
        <Header @add-todo="addTodo"/>
        <List :todos="todos" :deleteTodo="deleteTodo" :checkOne="checkOne"/>
        <Footer 
          :todos="todos" 
          v-show="todos.length" 
          :checkAll="checkAll"
          :clearAllDone="clearAllDone"
        />
      </div>
    </div>
  </div>
</template>

<script>
  import Header from "./components/Header.vue";
  import List from "./components/List.vue";
  import Footer from "./components/Footer.vue";

  export default {
    name: "App",
    components: { Header, List, Footer },
    data() {
      return {
        todos:JSON.parse(localStorage.getItem('todos')) || []
      }
    },
    methods: {
      // 用于添加一个todo，收到的参数是一个todo对象
      addTodo(todoObj){
        console.log('我是App组件，我收到了一个todo对象',todoObj)
        // 查找是否有同名的
        let result = this.todos.find( t => t.title === todoObj.title)
        // 有同名的
        if(result){
          alert('不能重复添加')
        }else{
          // 在todos数组的前方加一个todo
          this.todos.unshift(todoObj)
        }
      },
      // 用于删除一个todo，收到的参数是id
      deleteTodo(id){
        this.todos = this.todos.filter(t => t.id !== id )
      },
      // 全选 or 全不选
      checkAll(flag){
        this.todos.forEach( t => t.done = flag)
      },
      // 清除所有已完成的
      clearAllDone(){
        if(confirm('确定清除吗？')){
          this.todos = this.todos.filter(t => !t.done)
        }
      },
      // 勾选一个todo
      checkOne(id,flag){
        this.todos.forEach((t)=>{
          if(t.id === id){
            t.done = flag
          }
        })
      }
    },
    watch:{
      todos:{
        deep:true,
        handler(value){
          localStorage.setItem('todos',JSON.stringify(value))
        }
      }
    }
  };
</script>

<style>
/*base*/
body {
  background: #fff;
}
.btn {
  display: inline-block;
  padding: 4px 12px;
  margin-bottom: 0;
  font-size: 14px;
  line-height: 20px;
  text-align: center;
  vertical-align: middle;
  cursor: pointer;
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.2),
    0 1px 2px rgba(0, 0, 0, 0.05);
  border-radius: 4px;
}
.btn-danger {
  color: #fff;
  background-color: #da4f49;
  border: 1px solid #bd362f;
}
.btn-danger:hover {
  color: #fff;
  background-color: #bd362f;
}
.btn:focus {
  outline: none;
}
.todo-container {
  width: 600px;
  margin: 0 auto;
}
.todo-container .todo-wrap {
  padding: 10px;
  border: 1px solid #ddd;
  border-radius: 5px;
}
</style>